Vegetation Structure of Olea Ferruginea Royle Forests of Lower Dir District of Pakistan
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Pak. J. Bot., 41(6): 2683-2695, 2009. VEGETATION STRUCTURE OF OLEA FERRUGINEA ROYLE FORESTS OF LOWER DIR DISTRICT OF PAKISTAN MOINUDDIN AHMED, NASRULLAH KHAN, MUHAMMAD WAHAB, SALMA HAMZA, MUHAMMAD FAHEEM SIDDIQUI*, KANWAL NAZIM AND MUHAMMAD UZAIR KHAN Laboratory of Dendrochronology and Plant Ecology, Botany Department, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal, Karachi 75300, Pakistan. *Government Degree Science/Commerce College Landhi/Korangi, Karachi 74900. Abstract Thirty stands were sampled in forests dominated by Olea ferruginea during summer in 2008. Phytosociological attributes like relative frequency, density, basal area and absolute values such as density ha-1 and basal area m2 ha-1 of stands and species are presented. Based on importance values and floristic composition following 10 communities were recognized. 1, Olea- Punica community 2, Olea- Ficus community 3, Platanus-Morus communities 4, Olea– Ailanthus community 5, Morus-Celtis community 6, Olea-Acacia community 7, Olea- Morus community 8, Olea- Monotheca community 9, Olea- Quercus community 10, Pure Olea community. Most of these showed similar floristic composition with different quantitative values. Though no significant relation between density/basal area, elevation/density and elevation/basal area was obtained, however trends of these possible relations are described. Structure of Olea ferruginea and associated tree species in each stand is presented. Due to unbalanced forest structure and continuous disturbance, no future trends could be predicted for these forests. Introduction Olea ferruginea, a native broad leaved tree species of sub continent is distributed from 500 to 2000m in sub tropical, dry temperate and moist temperate regions of Pakistan. It was recorded from Afghan border, Western hills of Baluchistan, Dir, Chitral, Salt range, lower hills of Azad Kashmir, Waziristan, Swat and Murree hills (Baquar, 1969; Sheikh, 1993). This frost and drought resistant species has adapted 250mm to 1000mm per year precipitation and – 10oC to 40oC temperature, therefore can easily be planted on wide areas of arid, semi arid and dry temperate regions of Pakistan with minimum input. This way, watershed, microclimatic, environmental and edaphic conditions of the area can be improved through plantation of this tree. In addition its leaves, fruit and wood may be utilized as fodder, oil, fuel and construction respectively. A lot of quantitative phytosociological work has been published from various areas of Pakistan, however, little attention is paid to include single tree species or forest dominated by a single tree species. Beside some work of Cheema & Qadir (1973) on Acacia senegal, Beg & Khan (1984) on dry oak forests of Swat, Ahmed et al., (1990a 1990b, 1991 and 2008) on Juniper forest of Rodhmallazi, Juniper Track of Ziarat, Pinus gerardiana forest of Zhob District, Baluchistan, Cedrus deodara forest respectively and Siddiqui et al., (2009) on Pinus roxburghii of subtropical region of Pakistan have been reported. No comprehensive studies were carried 2684 MOINUDDIN AHMED ET AL., out in Pakistan on Olea ferruginea. Considering environmental, economical and ecological importance of Olea ferruginea, detailed vegetation study was carried out at 30 different locations of Dir District. It is hoped that present studies would increase our knowledge in terms of its community and association. Methods Since graveyards are considered least disturbed locations of any area (Hussain et al., 1993, Chaghtai et al., 1983, 1984), during summer 2008, 30 graveyards were sampled quantitatively in the various places of Lower Dir District. Point Centered Quarter method (PCQ) of Cottam & Curtis (1956) was used to evaluate the quantitative vegetational composition of these forests. At each sampling point, in each of four quadrants, the nearest tree species (>6cm dbh) was located and point to plant distance and diameter at breast height (dbh) were recorded. At each sampling stand, 20 PCQ points were taken at 25 meter interval. To increase the sample size for relative density, a second nearest tree (Ahmed, 1984) was also recorded. The distance was not measured for this tree but dbh was recorded. Density, frequency and basal area of each species were calculated following Mueller – Dombois & Ellenberg (1974). Species were ranked according to their importance value (Brown & Curtis, 1952) and the species with the highest importance value in the stand was considered the dominant species of the stand. Species were identified with the help of flora of Pakistan (Nasir & Ali, 1972). Results and Discussion Ecological characteristics of sampling sites, total density and basal area of each stand are presented in Table 1. The stands are distributed at lower hills from 685m to 1580m on fairly flat surface. The sampling area fall under the dry temperate broadleaved forest (Champion et al., 1965, Ahmed et al., 2006). Stand density ranged from 56 to 1089 tree ha-1 while stand basal area was recorded from 6.62 to 37.90 m2 ha-1. Olea ferruginea and associated species had diversity of density and basal area from site to site and within a stand (Table 2). Relationship between density/basal area, elevation/density and elevation/basal area are shown in Fig. 2. Density/basal area relation was found negative, non significant with wide variance. Low basal area is associated with higher density stands, due to a large number of young trees, while small density stands contained large sized trees in the study area. Ahmed et al., (1990b) found highly significant relation between these variable, in Juniper forests of Ziarat, Baluchistan, while Ahmed (1984) and Ahmed et al., (1990b) found no relation in Agathis australis forests in New Zealand and Juniper forests of Rodhmallazi, Baluchistan, respectively. A non significant trend was also observed from elevation/density regression analysis. This trend showed that density decreases with higher elevation. This species has restricted elevation range for its distribution and closed to its upper limit, its number gradually decreases. Elevation and basal area indicated positive but non significant relation with wide variance. Low density stands are located at higher elevation (elevation/density regression) and higher basal area is associated due to the presence of large trees in these stands. Density and basal area values greatly varies from site to site and no significant relation was found in between these variable of Olea ferruginea forests, therefore no proper conclusion could be made, however, as above, general trends may be described. VEGETATION STRUCTURE OF OLEA FERRUGINEA FORESTS 2685 Table. 1. Ecological characteristics of sampling sites. Absolute density per hectare and basal area meter square per hectare of stands are also presented. Stand Latitude Longitude Elevation Den. B.A Location No. N E in (m) ha-¹ (m² ha-¹) 1 Goron Khur 34 º 44 71 º 49 724 219 7.50 2 Bandagie 34 º 45 71 º 50 750 170 8.74 3 Utala Dushkel 34 º 45 71 º 50 814 130 28.91 4 Bagh 34 º 43 71 º 48 1090 154 14.74 5 Kattan Pahjron 34 º 43 71 º 48 1106 93 9.29 6 Anzoro Dushkhel 34 º 43 71 º 48 1320 158 5.66 7 Dera Kambar Meiden 34 º 57 71 º 49 1079 586 24.82 8 Manyal Meiden 34 º 57 71 º 47 1096 619 8.65 9 Khazana (Klurra) 34 º 45 71 º 50 685 724 10.23 10 Shamsabad (Kolalano Shah) 34 º 57 71 º 47 1157 175 6.62 11 Sher Khan (Meidan) 34 º 54 71 º 49 939 1089 15.01 12 Kotow Hajiabad 34 º 53 71 º 46 930 374 5.92 13 Kat Kala 34 º 43 71 º 56 938 697 14.18 14 Sarai Bala 34 º 43 71 º 56 966 163 10.20 15 Rahmanabad Talash 34 º 44 71 º 54 915 500 10.74 16 Mazuab Baba 34 º 39 72 º 02 719 266 16.39 17 Gambat Ziarat Talash 34 º 44 71 º 52 904 400 8.46 18 Ghurgi Yar Khan Banda 34 º 47 71 º 51 1088 177 7.53 19 Miayan Banda 34 º 55 71 º 71 804 196 22.04 20 Navagie 34 º 47 71 º 68 1350 211 37.90 21 Said Shah Baba 34 º 48 71 º 47 1385 85 29.80 22 Zakho Baba 34 º 49 71 º 50 1415 78 18.48 23 Qari Said Mula 34 º 50 71 º 49 1440 108 19.92 24 Mula Momen 34 º 53 71 º 48 1370 109 22.73 25 Tormang Baba 34 º 53 71 º 75 1580 101 18.88 26 Derie 34 º 46 71 º 43 950 88 25.96 27 Soghalie 34 º 45 71 º 47 970 90 34.05 28 Bagham Dara 34 º 43 71 º 52 826 101 22.68 29 Ghurgae 34 º 47 71 º 61 1135 56 11.19 30 Paito Dara 34 º 47 71 º 50 853 79 20.93 Note: Den. ha-¹ = density per hectare, B.A (m² ha-¹) = basal area meter square per hectare Olea ferruginea is the most abundant and widely distributed species. Out of 30 sites, it is absent in only Mazuab Baba area (Table 2) which may be due to cutting. The other widely distributed species, Morus alba was recorded from 13 location while Monotheca buxifolia and Punica granatum is distributed in 10 and 9 stands respectively. Out of 14 tree species recorded in sampling area, Quercus ilex, Ailanthus alltissima, Acacia modesta and Ficus palmata were found in 5 to 7 locations. Celtis australis was distributed in three stands, while Prunus armeniaca, Salix tetrasperma, Melia azedarach, Platanus orientalis and Juglans regia were rarely recorded from one or two locations. Phytosociological attributes indicates that Olea ferruginea occupied 100% of importance value forming a pure stand in 5 stands. In these stands its density ranged from 90 to 1089 ha-1 while basal area ranged from 9 to 38 m2 ha-1.